This is not related to a Toyota product but thought some of you who are mechanically inclined might have some ideas.

I have a 2006 Hyundai Elantra GT Hatchback with about 62,000 kms on it. It has a 5-speed manual transmission. While on a long trip last week, after about an hour of driving at highway speed, the transmission popped out of 5th gear. I didn't think too much of it at the time but it happened again several more times, always at a constant speed and always on relatively flat ground.

After parking for lunch for about an hours, I resumed my trip and everything was fine for about two hours when the problem started up again. During two days of city driving the problem did not reoccur.

I took the car to a dealer before returning home and they suspected it was something internal to the transmission. The technician suggested periodically downshifting into fourth gear and then back to fifth. Due to poor winter road conditions I had to do this anyway during the trip home. At no time did the transmission pop out of gear during this time. Once road conditions improved I left the car in 5th gear and about an hour later, it popped out of gear again. It continued this behavior for the remainder of the trip home, my only recourse being to hold the shift lever in the 5th gear position.

Does anybody have any ideas at to what might be the cause of this condition? If it is internal to the transmission, is if difficult or expensive to fix. Unfortunately my warranty expired only four weeks ago (go figure!).

Any suggestions would be most welcome.